1. Field of the Invention
The present invention relates to a vulcanizer in which a vulcanized object such as a green tire contained within a mold is vulcanized.
2. Description of the Related Art
Conventionally, a Bag-O-Matic type vulcanizer is known. This Bag-O-Matic vulcanizer is constructed such that an upper mold is an opening/closing type which rotates and moves vertically. However, in a vulcanizer in which a mold opening/closing mechanism can be also used as a tightening mechanism, a top link or a base serves as a component which applies a mold-tightening load to a mold.
FIG. 2 is a partially cutaway front view schematically showing a conventional Bag-O-Matic vulcanizer. In this drawing, an tipper mold 1 and a lower mold 2 are integrally and respectively fixed to bases 5.sub.1 and 5.sub.2 via a platen portion 3 and a heat insulating layer 4. The base 5.sub.1 on the upper mold 1 side is fixed to an upper frame 6.sub.1, while the base 5.sub.2 on the lower mold 2 side is fixed to the lower frame 6.sub.2. It should be noted that the upper mold 1 and the lower mold 2 are covered respectively by domes 7.sub.1 and 7.sub.2.
A side frame 8 disposed to the side of the lower mold 2 is provided with a large gear 9 indicated by a dotted line in FIG. 2. The large gear 9 is rotatable by an unillustrated small gear. Next, a link 10 is eccentrically supported by the large gear 9, thus causing the link 10 to move vertically together with rotation of the large gear 9. A main shaft 11 is attached to this link 10. The movement of the main shaft 11 causes the upper mold 1 to open and close, or to be tightened.
In this way, since the large gear 9 used for opening and closing the upper and lower molds is disposed at the side of the lower mold 2, there is almost no space at the side thereof. For this reason, it becomes difficult to provide a mold such as a split mold, which requires a large space. There has been a demand for improvement in this respect. It should be noted that, in FIG. 2, numerals 12, 13, 14 and 15 designate a side plate, a main shaft for a large gear, a product extruding device and an upper mold adjusting screw, respectively.
Additionally, in order to vulcanize a tire, for example, a three-part mold is used which is formed by upper and lower molds for forming shoulder and side sections of the tire, and a sector mold for forming a crown section. Since this sector mold is formed from a set ring, outer ring, guide ring, inner top plate, outer top plate, segment and the like, the size of the split mold markedly becomes large, and particularly, becomes wide in the radial direction of the tire.
On the other hand, a vulcanizer in which a mold opening/closing mechanism and a tightening mechanism are separately provided, is formed by a fixed lower mold disposed on a base frame and a movable upper mold supported by a frame above the fixed lower mold. Further, there is also provided a vertically moving/sliding mechanism which moves the upper mold vertically so as to open or close both upper and lower molds. Usually, the vertically moving/sliding mechanism is adapted to slide up and down between the vertical moving slide disposed at an upper side of the movable upper mold and a guide off a side slide. The vertical movement of the upper mold is performed by reversely rotating a male screw shaft supported by a cylindrical body which is fixed to the vertical moving slide. In this vulcanizer, the base plate which supports and fixes the lower mold portion is formed into a gate-shaped configuration. Further, provided in an upper portion of the upper mold is a screw-type, mold height adjusting mechanism.
However, even in this example, the space in the periphery of the lower mold is restricted by the side frames disposed at right and left sides off the mold. Accordingly, in the same way as the case of the above-described Bag-O-Matic vulcanizer, it was difficult to make a large-size mold based on the use of a split mold.
The above-described conventional vulcanizers have the following two drawbacks.
One is that conventional vulcanizers in recent years cannot use a mold, such as a split mold, for forming a tire whose outer diameter and height are large. As a result, the need arises for large facilities for accommodating the split mold, which increases product cost.
Another is the difficulty of a vulcanizer accommodating various types of molds, which results in lowering of productivity.